1. Field of the Invention
Embodiments of this disclosure relate to a semiconductor device and a method of manufacturing the same and, more particularly, to a three-dimensional (3-D) nonvolatile memory device and a method of manufacturing the same.
2. Description of the Related Art
A nonvolatile memory device retains data stored therein even though the supply of power is cut off. As the degree of integration of 2-D memory devices in which memory cells are formed in a single layer over a silicon substrate reaches a limit, there is proposed a 3-D nonvolatile memory device in which memory cells are vertically stacked in multiple layers from a silicon substrate.
The structure of a known 3-D nonvolatile memory device is described below.
FIG. 1 is a perspective view showing the structure of a known 3-D nonvolatile memory device.
As shown in FIG. 1, the known 3-D nonvolatile memory device includes a plurality of channel structures C extended in parallel in a first direction I-I′, a plurality of vertical gates 14 each placed between the channel structures C adjacent to each other and vertically protruded from a substrate 10, and a plurality of word lines WL coupled to the plurality of vertical gates 14 and extended in parallel in a second direction II-II′.
Each of the channel structures C includes a plurality of interlayer insulating layers 11 and a plurality of channel layers 12 which are stacked in an alternating manner over the substrate 10. Furthermore, a tunnel insulating layer 13A, a charge trap layer 13B, and a charge blocking layer 13C are interposed between the vertical gate 14 and the channel structure C.
In this structure, a plurality of strings is arranged in parallel to the substrate 10 and is stacked over the substrate 10. Accordingly, the degree of integration of memory cells can be improved as compared with a 2-D memory device.